
What are SGARs &
Why are they Dangerous to Wildlife?
More About SGARs
Thank you to https://www.savemasswildlife.org/ for this informative video!
How do SGARs work?
SGARs (Second-Generation Anticoagulant Rodenticides) are a type of poison used to control rodents like rats and mice. They work by interfering with the rodent's ability to clot blood, ultimately causing them to bleed internally and die.
How blood normally clots
Our bodies (and animals) need blood to clot when we get a cut or injury, so we don’t bleed to death. There are certain proteins in the blood that help it clot, and these proteins depend on vitamin K to work properly.
What SGARs do
SGARs, like brodifacoum, bromadiolone, and others, stop the body from using vitamin K. Without vitamin K, the blood can't clot properly, so the rodent starts to bleed internally.
Over time, the rodent loses so much blood that it dies, usually a few days after eating the poison. This delayed effect means the rodent doesn't immediately associate the poison with feeling sick, which makes it more likely to eat the poison.
Why are they used
SGARs are very potent and work even in small doses. Plus, because they are toxic over several days, a rodent can ingest multiple doses before showing any signs of illness, which increases the likelihood that the poison will work before the rodent gets suspicious and stops eating.
Because of this they can also pose a risk to non-target animals, like pets or wildlife, if they accidentally consume the poison.
Why Are SGARs dangerous to wildlife, pets, and children?
SGARs (second-generation anticoagulant rodenticides) are dangerous to wildlife for several reasons, and this risk extends beyond just professional pest control specialists to anyone who might encounter them in the environment. Here's why they pose a significant threat.
Secondary Poisoning
SGARs work by preventing blood clotting, which ultimately causes internal bleeding and death in rodents. When predators or scavengers (like owls, hawks, foxes, or even pets like dogs and cats) consume rodents that have ingested SGARs, they can also be poisoned. This phenomenon is called secondary poisoning. Even if the predator eats a rodent that isn't dead yet, the rodent could still have a lethal dose of the poison in its system, which can be passed up the food chain.
Bioaccumulation
SGARs are persistent in the environment and can accumulate in the bodies of animals over time. Unlike first-generation rodenticides, which break down relatively quickly, SGARs have a long half-life in the liver, meaning they can stay in an animal's system and continue to have toxic effects. This leads to the gradual buildup of toxins in both predators and prey.
Wide Range of Affected Species
SGARs are not selective in the animals they can harm. While they are designed to target rodents, they can affect virtually any animal that consumes a poisoned rodent. This includes non-target species like birds of prey, mammals, and even amphibians and reptiles that may ingest poisoned rodents or contaminated water.
Delayed Effects
The effects of SGAR poisoning can be delayed, sometimes taking days or even weeks to manifest. This makes it harder for people to spot the problem early, allowing the toxin to spread and impact a wider range of wildlife. For example, an animal may eat a poisoned rodent, then suffer from internal bleeding and die days or weeks later, before people notice any unusual behavior.
Threat to Ecosystems
Because SGARs can affect top predators and disrupt food chains, they can harm entire ecosystems. Predators that consume poisoned animals may experience reduced reproductive success, weakened populations, or even death, which can have cascading effects on the balance of species in that area.
Impact on Domestic Pets
Pets like dogs and cats can also be affected if they ingest SGARs directly or consume poisoned rodents. This is particularly dangerous because pets may not show symptoms immediately. Without prompt treatment, SGAR poisoning can be fatal.
Challenges in Treating Poisoning
Unlike some other types of rodenticide, SGAR poisoning is difficult to treat because the toxin can remain in the body for a long time and the symptoms may not be apparent until it is too late. This is another reason why they are so dangerous to wildlife—once an animal is poisoned, it may not receive the care it needs in time to survive.
Widespread Use
SGARs are commonly used in both residential and agricultural settings, which increases the risk to wildlife and pets. Many people may use these rodenticides without realizing the potential harm they can cause to the broader environment.
The heartbreaking story of MK, a Bald eagle in Arlington, MA who succumbed to SGARs.